import java.util.*;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: GodK
 * Date: 2024-09-25
 * Time: 15:04
 */
public class Main {
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        long n = in.nextLong();
        long ret = 0;
        if(Math.abs(n - (long)Math.sqrt(n)*(long)Math.sqrt(n)) >
                Math.abs(n - ((long)Math.sqrt(n) - 1))*((long)Math.sqrt(n) - 1)){
            ret = (long)Math.sqrt(n) + 1;
        }else ret = (long)Math.sqrt(n);
        System.out.print(ret*ret);
    }
//    public static void main(String[] args) {
//        Scanner in = new Scanner(System.in);
//        int a = in.nextInt();
//        int[] b = new int[3*a];
//        for(int i = 0;i < 3*a;i++)
//            b[i] = in.nextInt();
//        Arrays.sort(b);
//        int i = 3*a - 2;
//        int ret = 0;
//        for(int j = 0;j < a;j++){
//            ret+=b[i];
//            i-= 2;
//        }
//        System.out.println(ret);
//    }
}
